Shelters built from snow or ice may serve a variety of important functions. In areas that receive heavy snowfalls, where there are virtually no building materials available other than snow or ice, such shelters may provide humans with life-saving insulation from cold or other natural elements. Snow shelters are indispensable in times of emergency, and are often used in recreational applications, such as winter camping or ice fishing.
Building a shelter from snow or ice is a difficult job that requires a significant amount of skill. The shelter generally assumes the shape of a dome and is either sculpted from compacted snow or built from specially shaped blocks. Such blocks are cut from ice or compacted snow. The blocks must be angled slightly as they are stacked in circles of successively smaller diameters, so that they form an enclosure at the top of the shelter.
Molds have been used in the prior art to provide building blocks by packing the mold with snow or ice. These molds provide blocks of consistent shape, but generally require the user to make the block with the mold, and then place and adjust the block at the required location. Using conventional snow molds is difficult and impractical for several reasons. First, the size of the block requires the user to repeatedly lift considerable weight to complete the shelter. The resulting demand on human muscles in an already harsh environment saps normal human strength fairly quickly. Second, the weight of the snow packed mold can easily fracture such a mold when it is dropped. Third, the shape of the shelter is entirely determined by the user, and once a mistake is made, it is very difficult, if not impossible, to correct the mistake by repositioning the blocks already in place.
A slip form, wherein the block of snow or ice may be formed in place, has been found to solve the problem of lifting a heavy block to an elevated position. An empty slip form can easily be placed where the block is desired. The user may pack the slip form with snow or ice, and then remove the slip form while leaving the block in place. Smaller quantities of ice or snow may be lifted to the desired location, thus preserving a person's strength and reducing the risk of injury. However, a slip form alone cannot guide the placement of blocks to yield a structurally optimal shape for the snow or ice structure.
There is a great need for a relatively simple device that can be used without excessive physical effort to guide the construction of a shelter from snow or ice.